The potential of utilizing lignocellulosic biomass and waste plastics as viable feedstocks for conversion into liquid transportation fuels and other green-chemical products is now well recognized. Unfortunately, most existing biomass and waste plastic conversion schemes tend to focus on either traditional thermochemical (pyrolysis and acid hydrolysis) or biological (enzyme attack) pretreatment regimes and are, therefore, believed to be inefficient from a modem chemical engineering perspective. There exists, however, another very promising new approach that utilizes the amazing transformational properties of “supercritical water” (SCW) to rapidly depolymerize and liquefy giant biomass and/or waste plastic molecules into valuable simple sugar solutions and/or oily hydrocarbon mixtures, both of which are key chemical intermediates (commodities) that, in turn, are desirable products for makers of alternative transportation fuels (refiners) and green-chemical products (chemical companies). Indeed, and in recent years, two such green-chemical products producers have emerged in the marketplace; namely, Renmatix, Inc. (King of Prussia, Pa.) and Licella Pty Ltd. (New South Wales, Australia). Both of these newly emergent green technology companies utilize conventional slurry pumping (conveying) and static flow-through SCW reactor technologies to treat various biomass and/or waste plastic material feedstocks via supercritical water reaction. Conventional slurry pumps and static flow-through SCW reactors, however, require the transport (conveyance), heating and pressuring of great excesses of water in order to operate properly. The transport (conveyance), heating, and pressurizing of excess water is energetically and economically unfavorable.
With regards to the processing of waste plastics (and polystyrene in particular), another green-chemical product (crude oil from waste plastics) producer that has also recently emerged is Agilyx, Inc. (Portland, Oreg.). Agilyx describes itself as an “environmental technology and development company that extracts value from difficult-to-recycle mixed plastic waste streams.” To this end, Agilyx has purportedly developed a system capable of converting mixed waste plastics into a high-quality crude oil product (which, in turn, is sold to a local petroleum refinery (Tacoma, Wash.) for blending and subsequent refining). In brief, Agylix's technology may best be described as a modified pyrolysis process in which mixed waste plastics are first heated to form hydrocarbon gases, which gases are then subsequently condensed back into liquid form (thereby creating a hydrocarbon oil from what was once plastic). Because the unmitigated breaking (scission) of carbon-carbon bonds (of the polymeric material) via pyrolysis yields pairs of highly reactive free-radicals, a significant amount of char is necessarily formed (as the various sized free-radicals quickly bond and condense back together). The formation of any char products is undesirable because char is a useless solid material with no (or negative) commercial value.
Because of recent governmental initiatives to combat global warming and reduce domestic reliance on foreign petroleum products (through the development of alternative green energy and renewable chemical sources), and because of a strong societal desire to find alternative uses for biomass and waste plastics, the market potential for an alternative green technology platform that can rapidly transform biomass and/or waste plastics into liquid fuel and green-chemical products is believed to be unparalleled.
Accordingly, and although some progress has been made with respect to biomass and waste plastic materials conversion technologies, there is still a need in the art for new and improved biomass and/or waste plastic conversion machines, systems and related methods. There is also a need for transportable (by land or sea) machinery and methods that enable continuous supercritical water reaction of solid polymeric materials with minimal water usage and with changeable (tunable) residence times to thereby allow processing of a wide variety of different mixed polymeric feedstocks. The present invention fulfills these needs and provides for further related advantages.